Ignition system



D. B. HUGHES.

IGNITION SYSTEM.

APPLICATION men nov. 11, my

Patented Aug. 30, 1921.,

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UNITED STATES! PATENT OFFICE.

now :3. nnenns, or NEW YORK, N. Y., nssre von', BY mnsnn assronmrs, TOMOTOR wmrron a DEVICES COMPANY, A. CORPORATION or wEs'r vmoma IGNITIONSYSTEM.

Specification of Letters Patent.

Patented Aug. 30, 1921.

Application flied November 17,1911. Serial No. 660,783.

To all whom it may con cern:

Be'it known that I, Dow B. HUGHES, a

citizen of the United States, residin at New York cit in the county ofNew ork and State of ew York, have invented a certain ignition systems,and especially in those systems wherein the igniting arc' is produced bya low tension current, and is preceded by an arc produced by a hightension high frequency current.

It has been proposed to ignite a mixture in the manner above stated bymeans of a suitable source of current, such as a magneto, a condenserand a disruptive discharge coil suitably connected to the source ofcurrent and to the spark plug or spark plugs.

- and by a circuit breaker so arranged that when the latter is closed itshortcircuits the magneto, and when opened, permits the condenser to becharged and thence discharged, and constitutes part of the dischargecircuit of the condenser'with the gap at the circuit breaker serving asa primary spark gap for disruptive discharges of the condenser. Thecondenser thus discharges across the gap of the circuit breaker, andthrough the primary of the disruptive discharge coil, causing the highfrequency currents to be in-- duced in the secondary of the coil, andcausing the high tension high frequency are to be established at thespark plug. This are is then followed by an arc produced by theso-called primary or low tension current passing from the magneto.

The main object of the present invention is to provide an ignitionsystem particularlty of the type above stated, which is more e ficientthan those which have been tried out heretofore and wherein theelectrical results are obtained in a more satisfactory manner.

More specifically, the invention aims to provide an ignition systemhaving a circuit breaker which serves merely to short circuit and toopen the short circuit of the source of current, and having meansindependent of this circuit breaker for forming the spark gap acrosswhich the condenser is disruptively discharged, Further, the inventionaims to provide such an arrangement wherein the spark gap is traversedmerely by the high' frequency high tension current from the condenserand draws no current from "the main source of current, as may be thecase when the circuit breaker performs the two functions above stated.

The above objects are accomplished in a very effective manner y a systemhaving a plrcuit breaker for short circuiting and openmg the shortcircuit of a magneto, so that the condenser may be charged at thedesired intervals, and having also a separate spark gap which may haveaparallel connection with the c1rcu1t breaker, this spark gap beingtraversed-by the high frequency condenser currents and having assoclatedtherew'ithsome ,means such as an auxiliary condenser for preventing thesimultaneous passage of current across the gap from the mam source ofcurrent.

My lnvention may be further briefly summarized as consisting in certainnovel comblnatlons and arrangements of parts which will be described inthe specification and set forth in the appended claims.

In the drawings, Figure 1 is a diagrammatic representation ofa systemarranged for a four-cylinder engine and embodying one of the preferredforms of my invention; and Fig. 2 is a similar view showing amodification. 4

Referring now to Fig. 1, 10 represents the source of current which inthis case is an armature winding of a magneto here shown in the usualconventional manner. One terhaving in this instance four stationarycon-,

tacts 12", each of which is connected to a spark plug 13. Between thedistributer and tho magneto, Iprovide a condenser 14, and a disruptivedischarge coil 15. The primary 15= and. the condenser 14 are in seriesrelation and have one terminal connected to conductor 11 extendingbetween the magneto and the distributer, and the other terminalgrounded, so that the condenser and primary are in fact in parallel withthe magneto. The secondary 15 of the disruptive discharge coil 15 isconnected directly in circuit between the magneto and the distributer.It will be understood that the disruptive discharge coil has a lowinductance,

inasmuch as it is without an iron core, and the ratio of turns in theprimary and secondary is such as to result in an induced high frequencycurrent of proper voltage to obtain the desired results.

At 16 is shown a circuit breaker which is arranged to short circuit themagneto, the circuit breaker having one terminal connected to themagneto or to the conductor 11 extending between the magneto and thedistributer, and having its other terminal grounded. It will beunderstood that this circuit breaker, as well as the distributerare bothoperated by the engine at the proper speeds and proper relative speeds,the circuit breaker for a four-cylinder engine being driven at twice thespeed of the dist-ributer.

When the circuit breaker is closed, the magneto is short circuited, anda certain amount of energy is stored in the magneto during the intervalthat the circuit breaker is closed. When the movable distributer arm 12is in engagementwith one of the stationary contacts of the distributer,the circuit breaker, is opened and the ener y previously stored I in themagneto is a sorbed by the condenser, fully charging the latter. Inignition systems prior to my invention, and based on the principle ofoperation which has been explained above, the condenser is immediatelydisruptively discharged through the primary 15 and across the ap formedat the circuit breaker, the oscillations of the condenser which passthrough the primary, causing a high voltage high frequency current to beinduced in the secondary 15", which high frequency current causes an arcof low heat value to be established at one of the spark plugs so as tolead on or precede current from the magneto, this latter being of higheramperage than the high frequency current, and producing a hotter arcthan that produced by the high frequency current. This method whereinthe circuit breakerserves to short circuit the magneto and later as partof the condenser discharge circuit or as a spark gap device for thecondenser is successful, but it has the disadvantage that part of thecurrent from the magneto 1O follows across the gap with the highfrequency current.

To avoid this objection, and to provide a system which is more efiicientand effective than the prior systems, I provide in the discharge circuitof the condenser a separate spark gap device 17 for the oscillatingdischarges of the condenser, this spark gap device preferably havingterminals arranged at a fixed distance apart and being arrangedinparallel relation with the circuit breaker. In this case, one of theterminals of this spark gap 17 is connected to the conductor 11, and theother terminal is grounded.

To prevent the passage of the magneto current across the spark gap 17 atthe time a it is traversed by the high frequency currents produced bythe oscilla ng discharges of the condenser, I providn circuit with thespark gap 17, a condenser 18, which may be traversed by the highfrequency currents, but obstructs the passage of the (11- i rect orsubstantially direct current from the magneto.

The method of operation will now be apparent. As with prior systems, thecircuit" ,When the movable member of the distributer engages with theproper stationary contact of the distrlbuter, the circuit breaker isopened and the energy stored in the magneto rushes into the condenserand fills the same.

The condenser immediately .disruptively discharges with great rapidity,-not across the gap of the circuit breaker, but across the terminals ofthe spark gap 17 which is in parallel to the circuit breaker. In thesamemanner as before, this causes high frequency high high .tension currentsto be induced in the secondary 15 and results in the establishment of anarc of low heat value at the spark plug which is then followed by a lowtension. current from the magneto, producing the hot are suitable fortotal ignition of the mixture. The circuit breaker will remain opensubstantially during the interval that the movable member of thedistributer is in engagement with this particular stationary contact ofthe distributer, and as a result, the arc of high heat value may besustained for a considerable period by the high frequency current, orhigh frequency arc. 1

With this arrangement,the circuit breaker may be opened a greater amountthan in a system in which it serves as a spark gap for. the condenserdischarges, and'the break at the circuit breaker will be cleaner andwill not be accompanied by any material arcin The present arrangementhas a further advantage in that it is unnecessary to adjust the circuitbreaker very carefully to produce the desired results, it beingimmaterial just to what extent the circuit breaker is opened, inasmuchas the oscillating condenser discharges pass along the parallelconnection, including the spark gap 17.

This gap 17 forms the return path for the induced or high tension highfrequency currents, as well as for the primary high frequency currents.

tem for a multiple cylinder engine, that only a single condenser or onlya single disruptive discharge coil be employed. I may desire to employ asingle condenser with a number of disruptive discharge coils, one

. for each cylinder, or I may employ a separate condenser and a separatecoil for each cylinder.

For example, in Fig. 2, I have illustrated a system having thearrangement last referred to In this system, I employ as in the firstinstance a main source of current 10, a circuit breaker 15, a separatespark gap 17 having connected in serles therewith the condenser 18, thetwo being arranged in parallel to the circuit breaker, and I employ alsoa similar distributer 12 which is connected as before to the magneto bymeans of the conductor 11. In this case, however, each of the stationarycontacts 12 of the distributer are connected to a spark plug 19, to aseparate disruptive discharge coil 20, and to a separate condenser 21,the secondary of each coil and the plug being series relation, and theprimary and the condenser being in series relation, and the secondaryand plug, and the primary and condenser being in parallel or in separatelegs of a divided circuit. The method of operation is in this casesimilar to that of the system first described. and is as follows:

When a circuit breaker is closed, energy is stored in the armaturewinding, and when the movable member of the distributer engages one ofthe stationary contacts of the distributer, this energy rushes in andfills the particular condenser connected to that st a tionary contact ofthe distributer which happens to be engaged by the movable memberthereof. The condenser is then imme diately discharged through theprimary, through the condenser 18, and across the spark gap 17, with thesame results as first described. As the movable member of thedistributer engages the next stationary contact, by means of the nextcondenser and disruptive discharge coil, the same results are obtained.at the next spark plug. In each instance, however, the spark gap 17 andcondenser 18, while preventing the passage of current from the magneto,form a return path for the oscillating discharges of the condenser, andalso for the induced or secondary high frequency current.

Having thus described my invention, what I claim is:

1. In an ignition system, a spark plug, a source of current, acondenser, a disruptive "discharge coil having its primary connected tothe condenser, and its secondary connected to the spark plu means forcausing periodic charging o the condenser from the source of current andthe discharge thereof through said primary comprising a circuitbreaker'having connection with the source and with the condenser, saidsystem having means for preventing the condenser d1scharging across theterminals of the circuit the source, a disruptive. discharge coil, hav-111g its primary connected to the condenser and its secondary connectedto the spark plug, means for controlling the charging and discharging ofthe condenser, comprising a circuit breaker operatively connected to thesource and to the condenser, said condenser having a discharge circuitindependent of the circuit breaker, and including a spark gap and asecond condenser.

3. In an ignition system, a spark plug, a source of current connected tothe spark plug, a condenser connected to the source and adapted to becharged thereby, a disruptive discharge coil having its primaryconnected to the condenser and its secondary connected to the sparkplug, means for causing periodic charging and subsequent discharging ofthe condenser comprising a circuit breaker connected to the source so asto short-circuit the same and to open the short circuit, said condenserhaving a discharge circuit independent of the circuit breaker andincluding a fixed spark gap device across which the condenser may bedisruptively discharged, said spark gap device being connected to thesystem in parallel to the circuit breaker.

4. In an ignition system, a spark plug, a main source of current, acondenser connected to the source and adapted to be charged thereby, adisruptive discharge coil having.

its primary connected to the condenser and Its secondary connected tothe spark plug,

means for causing periodic charging and subsequent discharging of thecondenserco'inprising a circuit breaker connected to the source so as toperiodically short-circuit the same, said condenser having a dischargecircuit independent of the circuit breaker and including a spark gapdevice across which the condenser may be disru tively discharged, saidspark gap device having associated therewith means for preventing thepassage of current fromthe main source of current across said spark gap.device.

5. In an ignition system, means for forming an arc of low heat value bya high tension high frequency current which is followed by an arc ofhigh heat value produced by a current of comparatively lowtension,comprising a spark p ug, a source of current adapted to be connected tothe spark plug, so as to supply the low tension current, a condenserconnected to the source, a disruptiye discharge coil havmg a primaryconnected to the condenser, and a secondary connected to the spark plug,a circuit breaker for short-circuiting the source and for opening thecircuit so as to cause the condenser to be periodically charged andthence discharged, said condenser having a discharge circuit independentof the circuit breaker-including a fixed spark gap for causing the acondenser to be .disruptively discharged through the primary.

6. In an ignition system, a spark plug, a source of current, a condenserconnected to the source, a disruptive discharge coil having its primaryconnected to the condenser and its secondary connected to the sparkplug, means for controlling the charging and discharging of thecondenser, comprising a circuit breaker operatively connected to thesource and to the condenser, said condenser having an independent,normally open, discharge circuit adapted to become closed when subjectedto a predetermined potential surge. a

- 7. In an ignition system, a source of current, a disruptive dischargecoil, a condenser connected to the source through the primary oi" saidcoil, a spark plug connected to the secondary of said coil, a circuitbreaker operatively connected to the source and the primary of saidcoil, said condenser having an independent, normally open, dischargecircuit adapted to become 010 (1 under a predetermined surge ofpotential.

In testimony whereof, I hereunto affix my signature in the presence oftwo witnesses. DOW B. HUGHES. Witnesses:

H. R. SULLIVAN, A. F. KwIs.

